def generateNormals(self):
"""If :attr:`normals` is `None` or you wish for normals to be
recomputed, call this method to recompute them."""
norms = numpy.zeros( self._vertex.shape, dtype=self._vertex.dtype )
tris = self._vertex[self._vertex_index]
n = numpy.cross( tris[::,1] - tris[::,0], tris[::,2] - tris[::,0] )
normalize_v3(n)
norms[ self._vertex_index[:,0] ] += n
norms[ self._vertex_index[:,1] ] += n
norms[ self._vertex_index[:,2] ] += n
normalize_v3(norms)
self._normal = norms
self._normal_index = self._vertex_index
def generateTexTangentsAndBinormals(self):
"""If there are no texture tangents, this method will compute them.
Texture coordinates must exist and it uses the first texture coordinate set."""
#The following is taken from:
# http://www.terathon.com/code/tangent.html
# It's pretty much a direct translation, using numpy arrays
tris = self._vertex[self._vertex_index]
uvs = self._texcoordset[0][self._texcoord_indexset[0]]
x1 = tris[:,1,0]-tris[:,0,0]
x2 = tris[:,2,0]-tris[:,1,0]
y1 = tris[:,1,1]-tris[:,0,1]
y2 = tris[:,2,1]-tris[:,1,1]
z1 = tris[:,1,2]-tris[:,0,2]
z2 = tris[:,2,2]-tris[:,1,2]
s1 = uvs[:,1,0]-uvs[:,0,0]
s2 = uvs[:,2,0]-uvs[:,1,0]
t1 = uvs[:,1,1]-uvs[:,0,1]
t2 = uvs[:,2,1]-uvs[:,1,1]
r = 1.0 / (s1 * t2 - s2 * t1)
sdirx = (t2 * x1 - t1 * x2) * r
sdiry = (t2 * y1 - t1 * y2) * r
sdirz = (t2 * z1 - t1 * z2) * r
sdir = numpy.vstack((sdirx, sdiry, sdirz)).T
tans1 = numpy.zeros( self._vertex.shape, dtype=self._vertex.dtype )
tans1[ self._vertex_index[:,0] ] += sdir
tans1[ self._vertex_index[:,1] ] += sdir
tans1[ self._vertex_index[:,2] ] += sdir
norm = self._normal[self._normal_index]
norm.shape = (-1, 3)
tan1 = tans1[self._vertex_index]
tan1.shape = (-1, 3)
tangent = normalize_v3(tan1 - norm * dot_v3(norm, tan1)[:,numpy.newaxis])
self._textangentset = (tangent,)
self._textangent_indexset = (numpy.arange(len(self._vertex_index)*3, dtype=self._vertex_index.dtype),)
self._textangent_indexset[0].shape = (len(self._vertex_index), 3)
tdirx = (s1 * x2 - s2 * x1) * r
tdiry = (s1 * y2 - s2 * y1) * r
tdirz = (s1 * z2 - s2 * z1) * r
tdir = numpy.vstack((tdirx, tdiry, tdirz)).T
tans2 = numpy.zeros( self._vertex.shape, dtype=self._vertex.dtype )
tans2[ self._vertex_index[:,0] ] += tdir
tans2[ self._vertex_index[:,1] ] += tdir
tans2[ self._vertex_index[:,2] ] += tdir
tan2 = tans2[self._vertex_index]
tan2.shape = (-1, 3)
tanw = dot_v3(numpy.cross(norm, tan1), tan2)
tanw = numpy.sign(tanw)
binorm = numpy.cross(norm, tangent).flatten()
binorm.shape = (-1, 3)
binorm = binorm * tanw[:,numpy.newaxis]
self._texbinormalset = (binorm,)
self._texbinormal_indexset = (numpy.arange(len(self._vertex_index)*3, dtype=self._vertex_index.dtype),)
self._texbinormal_indexset[0].shape = (len(self._vertex_index), 3)